815241989 has 2 divisors, whose sum is σ = 815241990. Its totient is φ = 815241988.

The previous prime is 815241961. The next prime is 815242007. The reversal of 815241989 is 989142518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 740765089 + 74476900 = 27217^2 + 8630^2 .

It is a cyclic number.

It is not a de Polignac number, because 815241989 - 2⁸ = 815241733 is a prime.

It is a super-2 number, since 2×815241989² = 1329239001257352242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (815241929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407620994 + 407620995.

It is an arithmetic number, because the mean of its divisors is an integer number (407620995).

Almost surely, 2^815241989 is an apocalyptic number.

It is an amenable number.

815241989 is a deficient number, since it is larger than the sum of its proper divisors (1).

815241989 is an equidigital number, since it uses as much as digits as its factorization.

815241989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 47.

The square root of 815241989 is about 28552.4427851629. The cubic root of 815241989 is about 934.1763033671.

The spelling of 815241989 in words is "eight hundred fifteen million, two hundred forty-one thousand, nine hundred eighty-nine".